Metallurgical process



Patented Dec. 16, 1930' UNITED STATES PATENT OFF-ICE JOH H. wnrrn'or CRANFORD, NEW JERSEY, ASSIGNOB T BELL TELEPHONE LIABO-Y na'ronms, INCORPORATED, on NEW YORK, N. Y., A CORPORATION on NEW YORK nErALLuRGIcAL rnocnss No Drawing.

This invention relates to metallurgical processes, and particularly to the preparation of nickel and. nickel alloys for commercial use.

An object of the invention is to produce nickel and alloys'of nickel which are uniformly forgeable.

Heretofore, in the refinement of nickel and certain compositions of nickel, it has been customary to treat the molten-metal with a small amount of manganese followed by a small amount of magnesium. The addedmetals act as cleansing agents, the maganese combining with the'sulphur and the magnesium combining with the gases, such as' oxygen, etc.- a

-It has been found, however, that ingots produced in this manner are not uniformly forgeable due, it is thought, to small amounts of brittle nickel sulphide which remain, the theory being that nickel sulphide havlng a much lower melting point than nickel, the nickel sulphideforms between the grains of nickel upon solidification, thereby makmg the casting brittlev and'very difficult to work. A sulphur content as small as 005% is enough to make the metal brittle.

Among other addition agents which have been proposed, zirconium may be mentioned.

' 0 Thishas been used toincrease the workability of steel and certain alloys, but is found to be unsatisfactoryfor use'with nickel and nickel alloys.

According to the present invention, nickel andalloys of nickel are made uniformly 'forgeable by adding a small amount of tantalum or columbiumto the molten metal as a cleansing agent. In preparing the ingots, nickel, forexample, is melted in a suitable furnace. Near the endof the melt tantalum or columbium is added inthe form of an alloy in an amount suflici'ent to make the tantalum or columbium content of the molten bath about 0.25% to 0.50%. In either'case the second metal of the added alloy is nickel; in one case the added alloy preferably comprises about tantalum and 7 0% nickel', and in the other case about 31% columbium and 69% nickel. A mixture of tantalum and portion of the electrolyte is entrapped in the pores. When the plated nickel is melted the I Application filed December 15, 1926. Serial No. 155,114.

much higher temperature than nickel sulso phidel During the solidification the tantalum' sulphide or columbium sulphide is believed to be entrapped within the grains of nickel and therefore does not form in the grain boundaries. If the metal is maintained in its molten state long enough, and if suificient sulphur is present, at least a portion of the, tantalum sulphide or columbium sulphide will rise to the surface and may be drawn olf as slag. Tantalum and columbium have the prop erty of not only desulphurizing but also of deoxidizing the molten nickel. Most of the oxides of tantalum or columbium slag off at the top of the bath. The casting produced by thispro'cess is tough, free from blow-holes and capable of being worked without difli-- culty.

The process described above is particularly useful for treating such magnetic compositions of nickel and iron as are described in U. S. Patent No. 1,586,884 to G. W. El-

.men, issued June 1, 1926. In the manufacture of such alloys it is desirable to keep the -carbon content of the alloy as low as possible' and (hence electrolytic nickel, having 'a carbon content of .03% or less, is employed. This nickel is plated from a sulphate solution and since it is somewhat porous, a small electrolyte is decomposed and sulphur is absorbed by the molten-1 nickel. By employingtantalum or columbium as cleansing agents, the sulphur is combined with the added metal and the alloy is made uniformly forgeable without deleteriously alfecting its magnetic properties.

In the-claims the expression metal having properties similar to those of tantalum in- 100 cludes both columbium and tantalum and combinations of these metals.

What is claimed is:

1. The process of treating an alloy of nickel and iron which comprises adding to the nickel-iron allo while it is in a molten state an amount 0 another alloy of nickel and a substance having properties similar to those of tantalum, the nickel predominating, said amount being such that said substance will have a mass less than 1% of the total nickel-iron content of the resulting alloy.

2. The process of treating an alloy of nickel and iron which comprises adding to the alloy while in its molten state a small amount of a metal having properties similar to those of tantalum, said alloy having after a heat treatment magnetic properties better than those of iron, said magnetic properties being unafl'ected by the addition of said metal.

3. The process of treating a nickel-iron alloy in which the nickel predominates and which is capable of having developed therein by means of a heat treatment a permeability hi her than that of iron at low magnetizing orces which comprises adding to said alloy while in its molten state less than 1% of a metal having properties similar-to those of tantalum to render said alloy highly forgeable without impairing its permeabily- 4. The process of treating. a nickel-iron alloy in which the nickel predominates and which is capable of having developed therein by means of a heat treatment a permeability higher than that of iron at low magnetizing forces which comprises addin to said alloy while in its molten state a%out 25% to .5% of a metal having properties similar to those of tantalum to render said alloy highly forgeable without impairing its permeability.

In witness whereof, I hereunto. subscribe my name this 14th day of December A. D,

JOHN H. WHITE. 

